Patterns of weight-control behavior among 15 year old girls

Objective The objectives were to identify and predict patterns of weight-control behavior in 15 years old (yo) girls and to examine weight-control group differences in energy intake. Method Participants included 166 girls assessed every 2 years (ys) from age 5 to 15. Latent class analysis was used to identify patterns of weight-control behaviors. Antecedent variables (e.g., inhibitory control at 7 ys), and concurrent variables (e.g., BMI and dietary intake at 15 ys) were included as predictors. Assessments were a combination of survey, interview, and laboratory measures. Results Latent class analysis (LCA) identified four classes of weight-control behaviors, nondieters (26%), and three dieting groups, namely lifestyle (16%), dieters (43%), and extreme dieters (17%). Levels of restraint, weight concerns, and dieting frequency increased across groups, from nondieters to extreme dieters. Body mass index (BMI) at 5 ys and inhibitory control at 7 ys predicted weight-control group at 15 ys; for example, with every one point decrease in inhibitory control, girls were twice as likely to be extreme dieters than nondieters. Girls in the extreme dieters group were mostly classified as under-reporters and had the lowest self-reported intake, but ate significantly more in the laboratory. Discussion Among 15 yo girls, "dieting" includes a range of both healthy and unhealthy behaviors. Risk factors for membership in a weight-control group are present as early as 5 ys. Patterns of intake in the laboratory support the view that lower reported energy intake by extreme dieters is likely due under-reporting as an intent to decrease intake, not actual decreased intake.